Transport systems for textile yarn bobbins or cops in which pallets of the above type circulate on various segments of transport paths formed by rail-like transport channels for the base plates of the pallets have been known for a relatively long period of time, for example from Japanese Published, Non-Examined Patent Application JP-OS-52-25139. Pallets of this type for cylindrical or conical cross-wound bobbins are also known from German Patent Publication DE 34 16 387 A1, for example. In either case, it is common to prepare the cop or bobbin for subsequent yarn unwinding by locating and placing the leading end of the yarn at an accessible disposition on the cop or bobbin, e.g., by placement within the interior of the cop's tube or on the outer surface thereof.
To prepare cops with a yarn end preparation mechanism or machine, it is known from German Patent Publication DE 33 08 171 A1, for example, to remove the cops from their pallets to prepare the arbors and to transport the cops through the preparation device in this form. For this purpose each cop is gripped at the tip of its tube and, thus, the gripping device must conform to the tip of the tube. Moreover, the axial length of the tip of the tube unoccupied by yarn windings must be sufficient to enable gripping of the cop reliably without damaging the yarn windings thereon. In addition, when the leading end of the yarn is not to be positioned within the tube, but as an outer winding thereon, there must be sufficient space remaining beneath the gripping element on the tip of the tube.
For relatively large textile bobbins, such as conical or cylindrical cross-wound bobbins that have a correspondingly high weight, it is very difficult to generate a sufficiently strong clamping force on the tip of the tube without causing damage to the tube.
German Patent Application P 41 31 527.8 (which is not a prior art publication) discloses a pallet whose arbor and base plate respectively are produced from separate components that can be connected to one another by means of a lockable connection used for the purpose of selectively connecting any one of several different arbors to a uniform base plate construction when cops with varying inside tube diameters are to be prepared during a batch change. Accordingly, the lockable connection is designed such that the pallets whose arbors are to be changed can have the old arbor released by an auxiliary device and provided with a new arbor.